BEIJING, (Reuters) – Amnesty International has given its top 2015 human rights award to both Chinese dissident artist Ai Weiwei, a fierce critic of Beijing who has been banned from leaving China after an 81-day detention in 2011, and U.S. folksinger Joan Baez.

The Ambassador of Conscience Award recognises “those who have shown exceptional leadership in the fight for human rights, through their life and work”, Amnesty said in a statement yesterday.

“Through his work Ai Weiwei reminds us that the right of every individual to express their self must be protected, not just for the sake of society, but also for art and humanity,” said Salil Shetty, Amnesty’s Secretary General, in the statement.

Shetty said of Baez: “With her mesmerizing voice and unwavering commitment to peaceful protest and human rights for all, Joan Baez has been a formidable force for good over more than five decades”.

The joint award will be presented at a ceremony in Berlin on May 21, the statement said.

But it is almost certain that Ai, 57, will not be able to collect it as he remains under close surveillance and is unable to leave China.

Ai’s representative, Darryl Leung, said Ai could not accept interviews as “his situation is still sensitive”.

Chinese Foreign Ministry spokeswoman Hua Chunying said China has expressed its stance on Ai’s case many times. The ministry has previously said he was being investigated by law enforcement authorities.

In 2011, Ai was detained without any charge and held mainly in solitary confinement, sparking an international outcry. A court later upheld a $2.4 million fine against Ai for tax evasion.

The world-renowned artist maintains the charges were trumped up in retaliation for his criticism of the government.

Ai has been active despite his travel ban. Last September, Ai appropriated Alcatraz, the United States’ most famous former prison in San Francisco Bay, as a way to highlight the plight of activists held in detention.

In November 2013, the bearded artist started protesting his travel ban by putting flowers in the basket of a bicycle outside his Beijing studio and home. On Twitter, he said he would do it everyday until he “regains the right to travel freely”.